Antennas are commonly mounted atop a self-supported mast or pole. These structures are subject to swaying and bending under high wind loading, thereby mispointing the antenna in both elevation due to bending of the pole and azimuth orientation due to twisting of the antenna. This can be a severe problem in the application of point-to-point microwave directive antennas whose narrow beams must be precisely aligned. Moreover, monopole antennas are frequently polarized to permit the reception of a single signal and block signals polarized at different angles. The mispointing of monopole antennas can be addressed via construction of larger, stiffer, and more costly poles and/or guying the pole, which requires additional space, lacks aesthetic appeal and can have a negative environmental impact.
One antenna support is proposed in U.S. Pat. No. 3,605,108 to Crawford which discloses an antenna platform supported by a universal joint on a pole fixed to a foundation. Three rods extend between the foundation and the platform parallel to the pole. The rods have structural properties such that they deflect in a manner similar to the pole. A plurality of spacers provide a constant separation between the pole and the rods, and maintain the rods in parallel with the pole along their entire length. This complex construction produces additional compression and bending forces on the base due to the weight of the rods and their rigid connection to the base, and does not accommodate settling of the tower.
Another antenna support is proposed in U.S. Pat. No. 3,605,105 to Penzias which discloses an antenna platform supported on a pole. A flexible belt runs within the pole. The belt crosses itself as it passes from an antenna mirror down to the base and back via a system of pulleys. As the pole deflects, one portion of the belt lengthens while the other shortens, thereby rotating the antenna mirror. Such a complex system cannot easily be retrofitted to existing antenna support poles since the belt must run within the pole. For an antenna platform supporting multiple antennas, a complex belt and pulley system must be installed for each antenna, and correctly aligned with the orientation of that particular antenna.
Another antenna support is proposed in U.S. Pat. No. 2,510,059 to Black which discloses a self-leveling platform supported by a universal joint on a tower. A plurality of parallel rods are connected between the platform and the base. This construction is also complex and produces compression and bending forces on the base due to its weight and the direct rigid connection of the rods to the platform and the base, and does not accommodate settling of the tower.
It is an object of the present invention to provide an antenna mounting system which reduces or wholly overcomes some or all of the aforesaid difficulties inherent in prior known devices. Particular objects and advantages of the invention will be apparent to those skilled in the art in view of the following disclosure of the invention and detailed description of certain preferred embodiments.